Apparently Saudi Arabia has hundred of billions of dollars of assets in the US that would get frozen in the event of a lawsuit and any damages would be extracted from them, although the saudi's have said they will liquidate and remove any assets in the event the law passes

My guess is that the whole thing will just be completely unenforceable. It will be tried in US court and in all likelyhood Saudi Arabia won't even send a defense. Any damages awarded will by technically owed by the Saudi Royal Family but they won't pay any of it because US courts can't enforce it. They could potentially try to force the issue if any member of the family were to travel to the US but they would likely have diplomatic immunity which would protect them from any kind of enforcement on US soil.

TL;DR the whole thing is a PR move that will only worsen diplomatic relations and cost taxpayer dollars